Multiple lift type disk harrow



June 2, 1953 J. P. ROBERTSON 2,640,307

MULTIPLE LIFT TYPE DISK HARROW Filed May 18, 1950 6 Sheets-Sheet 1 36'619 L9 60 2 54 I 7 I a;

30 7 5? j /0 63a 65a IN V EN TOR.

J. P. ROBERTSON MULTIPLE LIFT TYPE DISK HARROW June 2, 1953 6Sheets-Sheet 2 INVENTOR. my ywfwvfop/w 477'0R/Y6Y Filed May 18, 1950June 2, 1953 J. P. ROBERTSON MULTIPLE LIFT TYPE DISK HARROW 6SheetsSheet 3 Filed May 18, 1950 INVENTOR; 2 lofiewfoow,

Jacfibow gig/u;

ATTOR VFY June 2, 1953 J. P. ROBERTSON MULTIPLE LIFT TY PE DISK HARROWFiledMay 1 1950 6 e heet 4 47a I/II m 1953 J. P. ROBERTSON 2,640,307

MULTIPLE LIFT TYPE DISK HARROW Filed May 18, 1950 S Sheets-Sheet 5 YINVENTOR.

June 1953 J. P. ROBERTSON 0 MULTIPLE LIFT TYPE DISK HARROW Filed May 18,1950 s Sheets-Sheet 6 IN V EN TOR;

UTE-E5 fie Patented June 2, 1953 UNITED- STATES PATENT OFFICE MULTIPLELIFT TYPE DISK HARROW Jackson Perry Robertson, Columbus, Miss.

Application May 18, 1950, Serial No. 162,764

My invention relates broadly to agriculture equipment and moreparticularly to a lift type multi-disc harrow.

This application is a continuation-in-part of my application Serial No.35.805 filed June 29, 1948 for Multiple Lift Type Disc Harrow.

One of the objects of my invention is to provide an improvedconstruction of multiple disc harrow including means for convenientlyand rapidly converting a single unit harrow to a multiple unit harrowand vice versa and maintaining the harrow in such converted conditionthroughout a desired operation.

Another object of my invention is to provide a construction of multipleunit harrow in which a screw-type strut is provided for maintainingmultiple unit harrow in ganged position while being readily adjustableto a position permitting the elevation of certain of the gangs foroperating the harrow as a single unit implement.

Still another object of my invention is to provide an improvedconstruction of pivot means for interconnecting the unit of a multipleunit harrow for insuring rigidity of the chassis structure of theimplement during ganged operation thereof.

Still another object of my invention is to provide an improvedconstruction of mounting means for the-disc gangs of a multiple discharrow for facilitating replacement and repairs to the equipment.

Still another object of my invention is to provide an improvedconstruction of hinged connection between the frame sections of amultiple gang harrow for facilitating orientation of one frame sectionwith respect to an adjacent frame section when converting from multipleunit operation to single unit operation and vice versa.

Still another object of my invention is to provide a construction ofjournalling means for the units of a multiple gang harrow forfacilitating rotation of the harrow discs during propulsion of theharrow.

A still further object of my invention is to provide adjustable meansfor a multiple disc harrow for controlling the depth of penetration ofthe earth by the harrow discs, the adjustable means being accurate andprecise for controlling the depth of penetration of the earth by thediscs with corresponding accuracy.

Still another object of my invention is to provide an improvedconstruction of locking means for maintaining the multiple units of theharrow in linearly aligned relation during harrowing operations.

Other and further objects of my invention reside in the improvedfeatures of construction of the multiple gang harrow set forth in thespecification'hereinafter following by reference to the accompanyingdrawings in which? 7 Claims. (01. 559-30 Figure l is a plan view of theimprovedmultiple unit harrow of my invention; Fig. 2 is a sideelevational View of the multiple unit harrow of my invention lookingin'the direction of arrow A in Fig. 1; Fig. 3 is a view similar to theview shown in Fig. 2 with one of the units of the multiple unit harrowraised to elevated position; Fig. 4 is an enlarged transverse sectionalview taken substantially on line 44 of Fig. 1 showing the arrangement ofthe harrow discs in one of the harrow units; (Fig. 5 is a horizontalsectional view taken substantially on line 55 of Fig. 4; Fig. 6 is afragmentary transverse sectional view taken substantially on line 66 ofFig. 5; Fig. 7 is a fragmentary vertical sectional view takensubstantially on line 'i-I of Fig. 5;

Fig. 8 is an elevational view of one of the bearing members employed forthe suspension of the harrow gangs in the structure of my invention;Fig. 9 is a transverse sectional view taken substantially on line 9--9of Fig. 2 showing the adjustable means for elevating and lowering theharrow units for controlling the depth of penetration of the harrowdiscs; Fig. 10 is a vertical sectional view taken substantially on lineill-I0 of Fig. 2; Fig. 11 is an elevational view partially in section ofthe adjusting means employed in the multiple unit harrow structure of myinvention; Fig. 12 is a transverse sectional view taken substantially online 12-42 of Fig. 11; Fig. 13 is a fragmentary plane view on anenlarged scale of the hinge structure provided by the multipleunits ofthe harrow of my invention; Fig. 14 is a transverse sectional view takensubstantially on line i l-l4 of Fig. 13; Fig. 15 is a transversesectional view taken substantially on line l5l5 of Fig. 13; Fig. 16 is afragmentary front elevational view looking in the direction of arrow B-in' Fig. 13 and. showing the locking means for the harrow sectionsbefore insertion of the securing bolt; Fig. 17 is a view similar to theview shown in Fig. 16 but illustrating the locking bolt in position, theview being taken substantially on line 17-11 of Fig. 13; Fig. 18 is atransverse sectional view taken substantially on line Iii-i8 of Fig. 13;Fig. 19 is a transverse sectional view taken substantially on line l9-l9of Fig. 13; Fig. 20 is a transverse sectional view taken substantiallyon line 20-40 of Fig. 1; Fig. 21 is a vertical sectional view takensubstantially on line 2|"-2| of Fig. 20 and Fig. 1; Fig. 22 is a sideelevational view of a modified form of my invention by which the rearharrow units may be selectively maintained in predetermined angularpositions with respect to the forward harrow units,

Fig. 23 is a view similar to the view shown in- Fig. 22 but'showingtheremote rear harrow unit raised and maintained in a 90 position withrespect to the plane of the axes of the forward harrow units; Fig. 24 isa fragmentary plan view of the front and rear frame structures utilizedin the form of my invention shown in Figs. 22-23 and showing the specialconstruction of hinge members which I provide for selectivelymaintaining the rear harrow units in selected angular relation to theforward harrow units; Fig. 25 is an enlarged fragmentary plan viewshowing the structure of one of the hinges'employed inthe structure ofFigs; 22-2 l; Fig. 26 is a verticalsectional view taken on the line26-45 of Fig. 25; and Fig. 27 is a vertical sectional view taken on line21-27 of Fig. 26.

Myinvention i directedto the type of multiple unit harrow described inmy co-pending application No. 35,895 supra ofwhich this application isa: contmuation-in-part and wherein I provide means. for adjusting thedepth of penetration of the earthby the harrow discs. I provide aleading and trailing or front and rear harrow unit where the leading.harrow unit is pivotally connected to a frame which couples to the hitchconnected to the tractor. The trailer harrow unit; is: pivotallyconnected with the leading harrow unit through special hinge means. andmay. be locked in coplanar relation by an arrangement of special boltfittings in accordance withmyinvention. The entire harrow structure may;be elevatedv or lowered by special screw means manually adjustable toprecisely and accurately, regulate the depth of penetration ofthevearths surface by the harrow discs. When the multiple :unit harrowstructure is to be operated in singlegang arrangementinstead of multiplegang arrangement the locking bolts are removedand the trailing. unit ismoved to a posidon-superimposed over the leading harrow unit. The massof the trailing harrow unit then becomes effective as ballast in aidingin the penetration of the earth by the discs of the leading har ow-u iI- -provide specialbearing and mounting means for-the gangs. ofdiscs tofacilitate rotation of therdiscsas the-harrow ispropelled by thepulling-tractor. Completely replaceable gang units ardproyidedaccordance with my invention for facilitating-'- replacement and repairof the narr w;

Referring to th drawings in more detail,- reference character Idesignates a hitch frame extending in a vertical direction and providingmeans for connection to a tractor through the lift arms designated at 2,3 and t extended-forwardly to thetractor. The lift arms 2, 3 andi" whicharecarried bythe angle frame member to.

of the forward substantially horizontally extending. frame member 8. Thesubstantially horizontallyi'extending frame member 8 providesmquntingmeans. for sets of harrow discs which are illustrated; moreparticularly in Fig. l. The substantially. horizontally extending framemembend issubstantiallyvin the shape of a trapezoid and is laterallybraced to provide a rigid frame by the angularly disposed angle framemembers 9 and I8. These angularly disposed angle frame members 9 and i8serve in coaction with the side frame angle members H and [2 as asupport for the sets of harrow discs shown more particularly inFig. 4.

The sets of harrow discs are arranged to revolve as the harrow is drawnforwardly over the field to be cultivated. The sets of harrow discs arerepresented mounted in their operative positions beneath thesubstantially horizontally extending frame 8'at id and i5 and consist ofassemblies bolted together by bolt members 16, one of the ends of whichis indicated in Figs. 2 and 3. The disc assemblies Hi and it aresymmetrical in arrangement and are indicated as, consisting of harrowdiscs i1, i8, i3 and 2.0 assembled-together in spaced relation bysleevelike spacer means indicated at 21, 22 and 23 con stituting theassembly i i. A reserve arrangement of disc and spacer membersconstitutethe assemblyin harrow unit 15 consisting of spaceddiscs Ha,48a, to and 28a, spaced by spacer members Zia, 22a and 23a,corresponding to'discs. i7, l8, l9 and 29 andspacer members M, 22' and23 of the harrowdiscassembly M. The axesof the harrow disc assemblies hiand lfi-extend at an obtuse angle with respect to each other and withrespect to the front of theframe member 8. The harrow discs arescalloped at their. peripheral edges for pulverizing th earth. Thespacer members 2| and-23'ofharrow disc assembly it are journalled inbearings Zdand 25.d epending from the horizontally extending framemember 8 while sleeve members-21a andiiia-are journalled in bearings 24aand 250. depending from the horizontally extending'frame memben 8.Inasmuch as the detailed constructionpf the bearings and thedetailedassembly-of the hare row disc units it and 15 are similar to thestructure and-mounting of the rearwardly disposed harrow units,reference is made to the descripa tionhereinafter following of therearwardly dis posed harrow units 26 and Zlfor a more com.- pleteunderstanding of both the mounting and assembly of the harrow units.

I arrange in a positioncoplanar. with the horizontally extending frame.member 8 a pair of. frame members 28 and 29 disposed rearwardly of theframe member 3. The frame members 28; and 29 are individually hinged tothe frame member 8'by means of very special constructions of hingeswhich are illustrated more clearly in Figs. l3, l4 and 15. ReferringtoFig. 13. it willv be observed that the rearwardly extending angl frame813 of frame member 8 provides a support for pairs of upwardly extendingplate members Ella and 31a which are welded to the top ofangle member81) in spaced positions thereonandextend beyond the rear edge of angle-member 8b. The rear frame 29 which is coplanar-.with-the forwardlyarranged frame member 3. is provided on its leading edge fram 29' withapair otter-- tically extending spaced plate members 32a and 33a whichextend between the spaced late members Staand 3la-and arepivotallyconnected thereto by bolt members 340: width-enabling, framemember 29 to be raisedfrom a substantially coplanar position with framevmembertas represented in Figs. 1 and 2 -to. a position'superimposedoverthe harrow disc assemblies carried by framemember 8. When thereaizframe mem her- -29 ispositioned coplanar with then-forwardly; framer. 13- 1 ngle framesgfltpandizsi abut each other as shown more clearlyin Figs. 14 and 15. The frame members 29 and 8 are maintained in thesaid coplanar relation by means of a locking bolt 36a which extendsthrough a pair of depending lugs represented at 31a and 38a. The lug 31ais shown more particularly in Figs. 16, 1'1 and 18 as having asubstantially U-shaped section which is recessed at the forward portionthereof as represented at 31a to allow the entry of the hexagonallyshaped head end 36a of bolt 36a. The lug 38a is formed by a pair ofdepending plates between which the bolt 360. extends and is secured bywasher and nut combination 3611". Thus the bolt 36a is carried in thelug 31a and substantially maintained against dislodgement and passesbeneath the angle frames 8b and 29' and between lugs 31a and 38a formaintaining frame member 29 in coplanar relation to frame member 8. Therear frame member 29" of frame member 29 extends toward the center ofthe implement and terminates in a depending plate 39a shown moreparticularly in Figs. 20 and 21. The depending plate 39a carries a boltmember 40 therein which'is directed transversely through a coactingplate 39 slotted at 39' to permit the entry of bolt 40, the plate 39being carried by the extension 28" of the frame member 28 havingcomplementary parts to the parts of frame member 29 heretoforeexplained. Thus when frame members 29" and 28" are aligned in coplanarrelation they may be locked in this relation by bolt member 49 which issecured in position by tightening nut and against slotted plate member39 represented in Fig. 21.

The frame member 28 is provided with symmetrically arranged componentparts which are identical with the component parts explained inconnection with frame member 29 including the plates 32 and 33 whichcoact with sets of plates 30 and 3| carried by angle frame 8b of framemember 8, the said plates being pivotally connected by bolts 34 and 35all arranged in a manner similar to the correspondingly numbered partsheretofore described by reference characters bearing subscripts a.Similarly the locking bolt 36 is arranged to extend through thedepending lugs 31 and 38 in a manner similar to the arrangement oflocking bolt 36a heretofore described. The frame members 28 and 29 maybe independently raised over the frame member 8 as represented forexample in Fig. 3 in which the frame member 28 is shown in elevatedposition while frame member 29 is shown in coplanar position withrespect to frame member 8.

The harrow disc assemblies 26 and 21 carried by frame members 28 and 29are symmetrically arranged and are displaced from the center of thimplement as shown in Fig. 1. The harrow disc assemblies 26 and 21 aredisposed on axes extending at an obtuse angle which is symmetricallyopposite to the obtuse angle on which the axes of harrow disc assemblies[4 and 15 extend. The discs are arranged in the harrow discs assemblies26 and 21 in positions which are in echelon with respect to the discs inthe forwardly disposed harrow disc assemblies M and I for insuring thepulverizing of the earth as the harrow is advanced over the field. Ihave designated the harrow discs in the harrow disc unit 26 at 4|, 42,43 and 44 spaced by sleeve members 45, 46 and 41 respectively. Thecomponent parts of the harrow disc assembly 21 have been designated bycorresponding reference characters bearing subscripts a where the discsare designated as lla, 42a, 43a and 44a spaced by sleeves 6 45a, 4Baand41a. In Fig. 41 have shown the manner of assembling the harrowdiscs withthe spacing sleeves therebetween and through which the bolt memberMia-extends and is secured therethrough by the headed end 480/ bearingagainst plate 490. arrangedat one end of the assembly and extendingthrough plate 50a. at the other end of the assembly and locked by meansof nut 48a" at'the end of the assembly. The assembly for discs M, 42, 43and 44 is carried ou in a similar manner.

The individually hinged frame members 28 and 29 are each polygonal inshape as represented inplan view in Fig. l and have the angle frameswhich interconnect the forward and rearward angle frames 28' and 28" and29' and 29" inclined at an angle extending toward the rear of theimplement. "The angle of inclination of the side frame members 28" and28" and angle frames 29" and 29- is such that when the multiple disc.assemblies are mounted thereon with the axes of the assemblies extendingnormeal to the direction of th angle frame members 28", 28", 29 and 29"the harrow discs are maintained at the proper obtuse angles for the mostefficient operation in coaction with the forwardly disposed harrowunits. 14 and i5.

The manner of journalling the rearwardly disposed harrow units 26 and 21has been illus- 2 trated more clearly in Figs. 4-8 wherein the manner ofsuspending the bearings from the angle frame members 29" and 29"" hasbeen clearly brought out. It will be observed that bracket members 5Iaand 52a. are secured to the vertically extending flange portions of theangle frame members 29" and 29" respectively by bolt members 53a and54a. The bracket members 5m and 52a depend downwardly and are providedwith horizontally extending portions Ma and 52a which serve. assupporting means :for the journal boxes 55a and 56a. Each journal box isformed as represented more particularly in Fig. 7 by upper and lowercomplementary parts 56a and 56a" which are secured by bolt :members 51a.and 5801. which extend through the horizontally extending flange 52a andare secured by fastening nuts 51a. and 58a to the top thereof. A similararrangement is provided for connecting bracket 5 la with journal box 55.The parts of the journal box 560. and 56a" enclose the combined spacedmember and sleeve bearing 41a. The sleeve bearing 41a is shown inelevation in Fig. 8 as including a multiplicity of .spaced flanges 41a,41a", 41a' and 41a"" distributed intermediate the end flanges 41a" and41a. The end flanges 41a and 41a" serve as spacer means bearing againstthe discs 44a and 43a while the intermediate flanges serve as bearingmeans to allow control rotation of the disc. assembly within the journalboxes 55a and 56a. Lubrication is provided through the journal boxes 55aand 5611 through the lubrication ports 69a and 61a. The associatedharrow disc unit :26 is mounted in a manner similar to the harrow discunit 21 on'brackets 5| and 52 employing component parts for the bearingssimilar to the component described for mounting harrow disc unit 21. l I

I provide very special means for controlling the depth of cut fortheharrow foreither of the positions of the-harrow; that is, with themultiple disc units operating in'coplanar relation or with the rearwardharrow disc units moved to superimposed position above the forwardharrow disc units. "This depth control mechanism is illus- 7 t e e rmrlea r nd es 3 em. -9- Th dept co tr l mechanisi cons ts-9 he r-9 screwmembers; QLoppositescrew th eaded pitch represented at GZ, and-.63.Screw member, 2 terminates in a block 64 :whichis-piyoted ate5 {to theup r ly extende hit h rame. I. T e-. .crew m mb 5 t mi ates i abhtkfifiwh hi i oted; e ween b cke :t moun ed. on angle na membe 8b att e scr. p t esh t am? memb 8- A lindr callmemb thi v n e ially extendin screwthreaded .cesses 68 and .59 :t re riehtand lef -ha d 5 c threa s t nb.etwee n 'ensesest e. sc hreaded members 6.2 andfie Ahand whe l fis-provid for revolving cylind ical member for retractin or extendi thescrew-th eads embers 5 2. an 163 depending uponithe di ectio .o ro atioo .hand wheel ,69. A nut .liLis pry ided-, on; s crew threaded member82, andcoac .withthe en O screw threaded recess t8 ving ,to *lQGkfjJhBex.- pension and contraction device into,v a predetermined setposition-when adjusted to-a desiredselected, position. .Withjramemembers .28 and 29 locked in coplanar relationwith frame member; 8 .the.entire harrow frame-may :be elevated about the pivotal connections lidand .ibwith the tractor hitch frame for therebycelevatingboth theforwardly disposed xharrowcdiseassemblies i4 and 15 asv well. as the..rearwardly disposed harrow disc assemblies -26. and '21 and clearingthe surfaceoverwhich the implement .is operated. :.-When the lockingbolts 36-and 36w are removed and ii'ramemembers 2a and e29 shifted toangular positions superimposed over the forwardlydisposed harrowdiscassemblies the double screw device continues to iunctioh to elevate theharrow= disc assemblies 4 d and l 5 above the surface over which theimplement operates and-inthisposition the tractor may. move the harrowreadily from one location to another d or to and from the field in whichi the implementisto be used. Where the de th of penetration of thesurface of the earth bytheharrovcdiscs mustbe controlled the double-.scr.ew may beaoperated by hand wheel 69 to exert pressurelbetweenizthe tr actor hitch frame I and the iramesfi and/01:8, -28, and29 for directin -the frames downwardly and inclined at such an anglethat; the harrow-:;discs ;.-willpenetrate :the earths surface.- to the.idesiredtdegree thereby controlling =thesdepthof cultivation by use ofthe -implement M .Oimyinvention.witlra .very. highdegree of preci-.sion.

1 In Fi s.,.22;+2'7: I, have shown a modified form ,o f ;.my inventionin; which. a special hinge con- .struction is .snbstituted. forithelplate. members :3 i 3 la, and 33and3aheretoiorefldescribed. In thismodified. arrangementthe rrame-memhers-zsand 29 are p vi i fi .td l iill i ltheirainteriorlsides with horizontally extending verticallysdisposed rplate members H. and; did, whichare welded to :the rear frame.mcmhc ssiland 29 resp c ive y, a d project-over thefront rame member 8.=Thefront frame member} parriescoacting vertically .ext ll 1 1 35'QlalfiSfl-Land 5112a. which; have a peripheral di ension. greater than180. 'The ,shape .of thee tes i 2 ;;.and 1 52a, -is shown moreclearlyg Mg. 26a wheredthercenter. .of the plate is located at 13c displaced abovethe stop-3.91am; SilllzffiGfiSzDflthB frame. members-- 8; 2 8 and -;2 9.{Ihat =.tc .-say,=the.plates 12and=12c are danger.;.than:...semi-.circles. and enable the plate members flinandJltw-tobe-journaled therein by 'holt members M and Ha-which extendthrough time cen r l a r ur s tlieinnla meme hers I Z; and 12a. enablesthe trailing frame members. and 29. to. be raised .with respect to the,leading frame v member 8 about thecenters provided .bybolt members 34.and 34a heretofore described-and thebolt members 14 and Maprovidedin thespecial hinge units constitutedby plates '1 i.-12 and li and 12a.

The circular plates "and 12a. are eachprovided with spaced apertureswhich I have designatedv at l5c,-l.6c,-'iia.and 18a inFig. 26 and whichcorrespond to similarly numberedapertnres without the sufiixla -providedinthe correspondinglyidentified plate 12. These spaced apertures areadjacent the periphe ral edge of eac cu ed s t en s ccdat uch incre eofdistance as will enable bolt members 14 to be detachably extendedtherethrough for selectively ma nta ni the ear .0 trailing frame. .membefiend i n. aselect cl ,anenl rpositionwith re- Shee to h o wa mtlc dsiframemembe For examplev in Fig. 22 the -re mote harrow unit 25 isshown elevated in a position at approximately 4 with respect to theplane of the-axes of the forward narrow units represented at I4 and isby the passage. of bolts it and i l-a. through apertures/i5 and idea inplates 12 and 12a. I referv to the aperturesuifi and 15a inorder.todesignate the corresponding apertures in the similar plate members72. and; 12a.

In Fig. 23 "I have shown. the'remote. trailing narrow unitdt elevated tovertical position in which the. frame 28 is. secured by bolt'M-passingthrough aperture 7"! in plate T2.

It will also be understood that the rear or trailing harrow units 29 and27 may both be moved to. a position directlyover the forwardorleadingharrow units it and i5 and maintained in position by bolt membersextending through apertures 73 and We in plate -members l2 and 12a.

The other parts of the modified form of equipment shown in Figs. 22-27are identified with the elements heretofore described in-connection withFigs. n21.

"In the operation of the harrow of my invention the complete unit asshown in'Figl 2 israised when it is desirable inturning the unit around.The entire unit also raised above theground level for transport to andfrom thelocations in which the unit isto be used. This raising operationis effected by the hydraulic system of the tractor and the three pointimplement-hook-up attachment which is al art of the tractor. I

Precision control of the depth of penetration ofthe harrow disc bladesis effected primarily by the hydraulic system and hook-up attachmerit.The harrow unit is .of the. order of' 73fl lbs. in weight and. the iourdiscgang's are originally'attached to the main frame at f xed angles.The arrangement is such that there is a tendency for the harrow toproduce a deeper depth of penetrationthan isdesirable, and also constitltesa load resistance that may'be greater than the tractor capacity.Under theseconditionsthedesired cp hof p rat on s rceul edby mov n thehydraulic controL lever on the tractor ,up ,or down for correspondinglyangular1y .sh. fting the complete narrow unit,

i si dl werins the. c mp te: narrow unit the hitch frame i remains in asubstantially vertical position throughout the up and down movement ofthe complete unity as. controlled. by the hydra l ys m andhoQk-up atachmen The frame mh rdeeisnated at: Balsa. rem ns s subtantially.horizcntalrositicn. Thailand wheel 69 on the cylindricalmember 61 may be revolved to operate the screw threaded members 62 and63 to regulate the depth of penetration of the rear sets of harrow discs26 and 21 in relation to the penetration by the front sets of harrowdiscs M and I5. If the adjustable cylindrical member 61 is revolved tolengthen the effective length of screw threaded members 62 and 63 therear end of frame member 8 and the coacting frames 28 and 29 move belowa horizontal gear line position and permits the rear sets of blades 26and 2'! to cut deeper than the front sets of blades M and [5. Byreversing the adjustment of hand wheel 69 the cylindrical member andassociated screw members 67 are shortened in their effective length sothat the frame member 8 and the associated frame members 28 and 29 willmove above a horizontal center line position and permit the front setsof disc blades l4 and. I5 to make a deeper penetration and deeper outthan the rear blades 26 and 21. The left and right hand threads on screwthreaded members 62 and 63 coactingwith the cylindrical member oradjustment strut B1 assure a very accurate and exact adjustment of theposition of the harrow discs.

By use of the implement of my invention the effective ballast of theimplement is readily controlled by either the distributing of the massof the harrow units in coplanar relation as represented in Figs. 1 and 2or concentrating the effective mass of the harrow units by thesuperimposed relation of the multiple disc units as represented by oneof such units in the position illustrated in Figs. 3, 22 and 23. I havefound the double screw device of my invention highly effective in theprecision control of the depth of cultivation.

While I have described my invention in certain of its preferredembodiments which have been found to be particularly effective inproduction, manufacture and use, I realize that modifications may bemade and I desire that it be understood that no limitations upon myinvention are intended other than may be imposed by the scope of theappended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows:

1. A multiple lift-type disc harrow comprising a coupling frameconnectible to a tractor, a frame member connected with said couplingframe, gangs of discs carried by said frame member, a pair of separateframe members disposed side by side individually hingedly connected withthe rear of said first mentioned frame member, and movable through anorbit appreciably greater than 90 degrees in the direction of said firstmentioned frame member, gangs of discs carried by said pair of framemembers, said first mentioned frame member carrying connecting means onthe trailingedge thereof, and said pair of separate frame memberscarrying connecting means on the leading edges thereof aligned with theaforesaid connecting means, and disconnectible means interconnecting thealigned connecting means on both said frame member and the rearwardlydisposed separate frame members for maintaining said pair of framemembers in coplanar relation with respect to said first mentioned frame.

2. A multiple lift-type disc harrow as set forth in claim 1 which alsoincludes additional disconnectible means interconnecting said pair ofseparate frame members, all of said disconnectible means whendisconnected permitting said separate frame members to be individuallyand separately moved from a coplanar position with respect to said firstmentioned frame member to a position over and above said first mentionedframe member.

3. A multiple lift-type disc harrow as set forth in claim 1 in whichsaid pair of separate frame members have individual widths which aresubstantially one-half the width of said first mentioned frame memberand where said pair of frames may be selectively oriented to a positionover said first mentioned frame.

1. A multiple lift-type disc harrow as setforth in claim 1 in which theconnecting means on the trailing edge of said frame member aresubstantially U-shaped and depend downwardly beneath the said framemember and wherein the connecting means on the leading edges of the pairof separate frame members comprise depending spaced members extendin inalignment with the aforesaid U -shaped members and wherein thedisconnectible means interconnecting the aligned connecting means onboth said frame and the rearwardly disposed separate frames constitutedby both members extend through said U-shaped members and between saiddepending spaced members and are fastened with respect thereto.

5. A multiple lift-type disc harrow as set forth in claim 1 in which theconnecting means on the trailing edge of said first mentioned framemember depend beneath the plane of said frame member and where theconnecting means on the leading edges of said pair of separate framemembers depend beneath the planes of said separate frame members inalignment with the aforesaid connecting means and wherein thedisconnectible means interconnecting the aligned connecting meansextends below the planes of both said frame and said pair of framemembers when said pair of frame members and said frame member aredisposed in coplanar relation.

6. A multiple lift-type disc harrow as set forth in claim 1 in whichsaid pair of separate frame members abut with each other at the trailingedges thereof and have disconnectible means for fastening the rear edgesof said pair of frame members in coplanar relation with respect to saidfirst mentioned frame member and in coplanar relation with each other.

7. A multiple lift-type disc harrow as set forth in claim 1 in whichsaid pair of separate frame members terminate in mutually abuttingmenibers wherein one of said members carries a disconnectible meanstherein and the other of said members includes a downwardly disposedsubstantially V-shaped notch operative to engage said disconnectiblemeans when said pair of separate frame members are disposed in coplanarrelation with respect to said first mentioned frame member and incoplanar relation with each other.

JACKSON PERRY ROBERTSON.

References Cited in the file of this patent UNITED STATES PATENTS Number

